226
ACUS01 KWNS 170602
SWODY1
SPC AC 170600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Tue Jun 17 2025

Valid 171200Z - 181200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF WESTERN AND CENTRAL KANSAS...

...SUMMARY...
Severe thunderstorms producing damaging winds, hail, and possibly a
few tornadoes are expected today across parts of the central Plains
and lower to mid Missouri Valley. Outside of this area, marginally
severe storms will be possible across a large part of the central
U.S. Storms with isolated severe winds gusts may develop in parts of
the central Appalachians and Mid-Atlantic.

...Synopsis...

A low-amplitude upper shortwave trough over the Four Corners this
morning will eject east into the central/southern Plains by this
evening. This will result in a belt of enhanced southwesterly flow
across the central High Plains into KS/OK and the MO Valley. At the
surface, south/southeasterly low-level winds will maintain rich
boundary-layer moisture across southern KS and OK ahead of
south/southeast-advancing cold front. This moisture will wrap around
a broad low over the central/southern High Plains into the foothills
of eastern CO as well. Outflow from prior day`s convection (which
may be continuing across south-central/southeast KS/northern OK this
morning) will also extend eastward across central/southern KS
through peak heating. These boundaries, aided by the ejecting upper
shortwave trough and an increasing south/southwesterly low-level jet
during the evening across OK/KS will focus severe thunderstorm
develop through tonight from eastern CO into KS/OK and portions of
MO.

Additional thunderstorm activity is expected across much of the
Southeast into the Mid-Atlantic vicinity, though severe potential
will remain more isolated.

...CO/KS/OK/MO vicinity...

Isolated thunderstorms are expected along the CO foothills in a
moist, post-frontal upslope flow regime during the afternoon/early
evening. Cool temperatures aloft will support steep lapse rates amid
elongated/straight hodographs, indicating large to very large hail
potential. As convection develops eastward into better low-level
moisture, clustering may occur over eastern CO, leading to an
increase in damaging wind potential by late afternoon/early evening.
Forecast guidance suggests upscale development should occur near to
CO/KS border, aided in part by the south/southeast-advancing cold
front and a strengthening (40-50 kt) southwesterly low-level jet.
Most forecast guidance, including CAMs, develop a swath of 70-100
mph 10 meter winds as a bowing MCS moves across western and central
KS. Strong heating during the day and ample boundary layer moisture
will support a corridor of 2000-4000 J/kg MLCAPE within a steep
lapse rate environment. Swaths of damaging winds, with some greater
than 70 kt, will be possible. The favorable parameter space and
synoptically evident damaging wind pattern, an upgrade to Moderate
risk (level 4 of 5) has been introduced. The bowing MCS is expected
to track across KS and parts of northern OK and into southwest MO
during the night time hours, with gradually waning severe potential
with eastward extent into MO late tonight.

In addition to a damaging wind event during the evening/nighttime
hours, some potential for large to very large hail, and more
conditionally a couple of tornadoes, exists across portions of
central/eastern KS in the vicinity of an outflow boundary. Greater
uncertainty exists across this area as morning convection may
largely inhibit afternoon thunderstorms depending on the extent of
longevity of early storms. Nevertheless, supercell wind profiles
within a strongly unstable environment will be present. Any storms
developing along outflow could quickly become severe and produce
significant hail and a couple of tornadoes.

...Southern PA/WV/VA/MD...

Strong heating and a seasonally moist airmass are expected today
across the central Appalachians/southern Mid-Atlantic vicinity
within a modestly sheared environment. Thunderstorms are expected to
develop over higher terrain by early afternoon and spread east
through early evening. Some clustering may occur and isolated strong
to severe wind gusts may occur, particularly across parts of VA/MD
where stronger instability is forecast.

..Leitman/Weinman.. 06/17/2025

$$